package com.zhuang.io.nio.demo;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;

public class GroupChatClient {

	// 定义相关的属性
	private final String HOST = "127.0.0.1"; // 服务器的ip
	private final int PORT = 6667; // 服务器端口
	private Selector selector;
	private SocketChannel socketChannel;
	private String username;

	public static void main(String[] args) throws Exception {

		// 启动我们客户端
		GroupChatClient chatClient = new GroupChatClient();

		// 启动一个线程, 每个3秒，读取从服务器发送数据
		new Thread() {
			public void run() {

				while (true) {
					chatClient.readInfo();
					try {
						Thread.currentThread().sleep(3000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
		}.start();

		// 发送数据给服务器端
		Scanner scanner = new Scanner(System.in);

		while (scanner.hasNextLine()) {
			String s = scanner.nextLine();
			chatClient.sendInfo(s);
		}
	}

	// 构造器, 完成初始化工作
	@SuppressWarnings("static-access")
	public GroupChatClient() throws IOException {

		selector = Selector.open();
		// 连接服务器
		socketChannel = socketChannel.open(new InetSocketAddress("127.0.0.1", PORT));
		// 设置非阻塞
		socketChannel.configureBlocking(false);
		// 将channel 注册到selector
		socketChannel.register(selector, SelectionKey.OP_READ);
		// 得到username
		username = socketChannel.getLocalAddress().toString().substring(1);
		System.out.println(username + " is ok...");

	}

	// 向服务器发送消息
	public void sendInfo(String info) {

		info = username + " 说：" + info;

		try {
			socketChannel.write(ByteBuffer.wrap(info.getBytes()));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	// 读取从服务器端回复的消息
	public void readInfo() {

		try {

			int readChannels = selector.select();
			if (readChannels > 0) {// 有可以用的通道

				Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
				while (iterator.hasNext()) {

					SelectionKey key = iterator.next();
					if (key.isReadable()) {
						// 得到相关的通道
						SocketChannel sc = (SocketChannel) key.channel();
						// 得到一个Buffer
						ByteBuffer buffer = ByteBuffer.allocate(1024);
						// 读取
						sc.read(buffer);
						// 把读到的缓冲区的数据转成字符串
						String msg = new String(buffer.array());
						System.out.println(msg.trim());
					}
				}
				iterator.remove(); // 删除当前的selectionKey, 防止重复操作
			} else {
				// System.out.println("没有可以用的通道...");

			}

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}
